feeding habits and navigational cues used during migration is needed 

 before the effects of platforms on marine mammals can be assessed with 

 appreciable certainty. 



Besides physical presence of the platform in the migratory path of 

 the whales, noise and oil seepage could have effects on the behavior of 

 the marine mammals. 



Noise was recorded from every platform where the interview and 

 sighting card program was conducted in Santa Barbara Channel and 

 correlated to their concurrent activities. This information is being 

 evaluated with respect to the cetacean hearing capability and the 

 frequency of sightings around the platform. There is constant noise 

 associated with the operation of offshore platforms although it varies 

 in type, intensity, and frequency. While it is assumed that the marine 

 mammals can hear the noise, its effect and the response of the mammals 

 are not known. 



Natural gas and oil seepage may result from offshore production. 

 However, marine mammals are present in many areas of natural seepage 

 such as Coal Oil Point, and animals have been observed swimming through 

 areas of oily water. 



Although the cetaceans were the primary subject of this study, 

 pinnipeds were also included. California sea lions, Zalophus 

 californianus , did not seem to be at all adversely affected by the 

 various OCS structures. They have been frequently reported resting on 

 marker buoys, floating aids, and low deck platforms in the Santa 

 Barbara Channel area. The reason for this is probably because the 

 platforms create a very rich underwater environment. The submerged 

 portions of the platforms support a diverse invertebrate community 

 (Simpson, 1977) which attract higher organisms including fish which in 

 turn attract sea lions. Usually, large numbers of sea lions can be 

 seen around almost all of the platforms. 



Study Area II: Cook Inlet 



The program ran very smoothly in this area. There was a general 

 acceptance of the study and lots of cooperation. Two companies. Union 

 and Texaco, did not participate in the study. Union management felt 

 that their employees were too busy to ever see any marine mammals and 

 the Texaco representative felt that since only a few workers were ever 

 out on their platform, it would not be a very useful study point. 

 Nevertheless, this project was able to cover the main fields in the 

 Cook Inlet. 



There are four major oil fields in the Cook Inlet. The Granite 

 Point Field is the northernmost in the inlet and consists of AMOCO's 

 platforms Bruce and Anna and Union's Granite Point Platform. Southwest 

 from this point is the Trading Bay oil field which is being produced 



:-25 



